The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 09, 1991
Filed:
Sep. 15, 1989
Shotaro Tanaka, Neyagawa, JP;
Masao Ikezaki, Neyagawa, JP;
Hiroshi Sasanuma, Yawata, JP;
Yukiko Hase, Machida, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
N. V. Philips' Gloeilampenfabricken, Bindhoven, NL;
Abstract
A communication control method for use in a communication system including a plurality of communication control apparatuses interconnected through an information transmission path, each of the communication control apparatuses including a packet transmission/reception unit, a timer unit and a controller unit. When a first communication control apparatus has become unable to perform communication due to accidental power-off or a power supply failure or the like in the course of communication with a second communication control apparatus (which has been brought into a locked state by the first communication control apparatus), the invention prevents the second communication control apparatus from being left permanently in the locked state. In that case, the second communication control apparatus transmits a lock confirmation packet to the first communication control apparatus to make lock confirmation as to whether the locked state is to be maintained, when the second communication control apparatus does not receive any communication packet from the first communication control apparatus for a predetermined period of time. When no reply to the lock confirmation is received or alternatively when an unlock authorization packet is received by the second communication control apparatus, the second communication control apparatus releases itself from the locked state.